package com.qingchi.base.platform.weixin;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.AlgorithmParameters;

/**
 * @author qinkaiyuan
 * @date 2020-03-26 13:30
 */
public class WxDecode {
    public static String decrypt(String data, String key, String iv) throws Exception {
        //被加密的数据
        byte[] dataByte = Base64.decodeBase64(data);
        //加密秘钥
        byte[] keyByte = Base64.decodeBase64(key);
        //偏移量
        byte[] ivByte = Base64.decodeBase64(iv);
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
        AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
        parameters.init(new IvParameterSpec(ivByte));
        // 初始化
        cipher.init(Cipher.DECRYPT_MODE, spec, parameters);
        byte[] resultByte = cipher.doFinal(dataByte);
        if (null != resultByte && resultByte.length > 0) {
            return new String(resultByte, StandardCharsets.UTF_8);
        }
        return null;
    }
}
